//  This file is part of YamlDotNet - A .NET library for YAML.
//  Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Antoine Aubry and contributors
    
//  Permission is hereby granted, free of charge, to any person obtaining a copy of
//  this software and associated documentation files (the "Software"), to deal in
//  the Software without restriction, including without limitation the rights to
//  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
//  of the Software, and to permit persons to whom the Software is furnished to do
//  so, subject to the following conditions:
    
//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.
    
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.

using System.Collections.Generic;
using System.Globalization;
using YamlDotNet.Core;

namespace YamlDotNet.Serialization.Utilities
{
	internal sealed class ObjectAnchorCollection
	{
		private readonly IDictionary<string, object> objectsByAnchor = new Dictionary<string, object>();
		private readonly IDictionary<object, string> anchorsByObject = new Dictionary<object, string>();

		/// <summary>
		/// Adds the specified anchor.
		/// </summary>
		/// <param name="anchor">The anchor.</param>
		/// <param name="object">The @object.</param>
		public void Add(string anchor, object @object)
		{
			objectsByAnchor.Add(anchor, @object);
			if (@object != null)
			{
				anchorsByObject.Add(@object, anchor);
			}
		}

		/// <summary>
		/// Gets the anchor for the specified object.
		/// </summary>
		/// <param name="object">The object.</param>
		/// <param name="anchor">The anchor.</param>
		/// <returns></returns>
		public bool TryGetAnchor(object @object, out string anchor)
		{
			return anchorsByObject.TryGetValue(@object, out anchor);
		}

		/// <summary>
		/// Gets the <see cref="System.Object"/> with the specified anchor.
		/// </summary>
		/// <value></value>
		public object this[string anchor]
		{
			get
			{
				object value;
				if (objectsByAnchor.TryGetValue(anchor, out value))
				{
					return value;
				}

				throw new AnchorNotFoundException(string.Format(CultureInfo.InvariantCulture, "The anchor '{0}' does not exists", anchor));
			}
		}
	}
}